Who created this site, and is it expensive to maintain?, and yet, in what year was created this site?
I'm just curious.
In regards to who made it, I'm pretty sure (as in I'm guessing) that this is a fork of danbooru, but obviously heavily edited and better. I'm not sure about the rest of your questions though.

P.s. I know this is two months later, but I figured you'd appreciate a reply ;)